In recent, with the development of information-oriented society, cloud services using a high-speed data transfer and large capacity storage have been actively ongoing. The cloud service refers to an environment that enables the distributed processing of a large capacity database in the virtual space of the Internet with the help of a web-based application and various terminals such as desktop PCs, mobile phones, notebook PCs, PDAs, etc. to fetch or process the data.
Thus, in the cloud computing environment, a service provider integrates servers (in data centers) that are distributed to multiple locations with virtualization technology to provide services that users need.
In this case, the user selects guest machines to be used on a virtual space created through the virtualization technique (a guest machine means a conceptual logical equipment on the virtual space and may be understood as a kind of virtual machines including an operating system, security and the like) as much as needed at any point in time, instead of directly installing the necessary resources such as an OS (Operation System), storage, application, security, etc. in his/her own terminal. Therefore, the user does not pay purchasing cost for the respective computing resources, but pays the cost for the computing resources based on the amount of the use, which leads to economic benefits.
In addition, the user has benefits that can perform a task that requires a large-capacity storage device and a high-performance computing resource by connecting to the cloud network through a terminal having a capability of network connection and performing arithmetic functions and receives advanced services in any place.
However, in the cloud computing environment, because of issues of security threats such as external hacking attacks, security issue that can protect the assets from the threats has emerged as the most important challenge. Existing cloud security system merely relies on security equipment provided from the service provider and collect and manage security events that occur segmentally fragmentarily.